/**
 * vmshell - An very minimal shell
 *
 * Author: Renê de Souza Pinto
 * Date: Mar, 2009
 *
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

#define MAXBUFFER 1024

extern char **environ;

int main(int argc, char **argv)
{
	int status;
	pid_t child;
	char line[MAXBUFFER];
	char stop = 0;

	/**
	 * An very simple loop to do two things:
	 *
	 * 	1) Read the user command line
	 * 	2) Check for exit command or fork proccess
	 */
	while(!stop) {
		printf("minimalshell> ");
		fgets(line, MAXBUFFER, stdin);
		line[strlen(line) - 1] = '\0'; /* drop \n */

		if( strncmp(line, "exit", 4) == 0) {
			stop = 1;
		} else {
			/* fork proccess */
			if( (child = fork()) ) {
				/**
				 * This is the father (shell), so wait for
				 * child termination
				 */
				waitpid(child, &status, 0);
			} else {
				/**
				 * This is the child, execute the command
				 */
				execve(line, NULL, environ);

				/* Something was wrong, show error message */
				printf("\nCannot execute: %s\n", line);
			}
		}
	}

	return(0);
}

